The present invention relates to a device and method for controlling registration in a printing press.
U.S. Pat. No. 6,167,806, hereby incorporated by reference herein, describes a control device for controlling the printing of a web of material in a rotary printing press from a control panel. As described in the patent, an operator receives a printed product from the printing press and lays the product on an analysis table. The operator flips through the product to check various attributes, for example, proper color, ink key application, and proper registration.
For example, a newspaper printing press 100, schematically shown in FIG. 2 as a two-tower press each with two-wide plate cylinders, may print a four-color newspaper 10 in an eight page format, with pages A1, A8, and A2, A7 being printed on one web 103 and pages A3, A6 and A4, A5 on another web 102. The webs are combined in a folder 110, which folds and cuts the webs 102, 103 so that newspapers 10 result. Thus a two-image-wide plate cylinder 120 may print the cyan image for A1, A8, as shown in FIG. 3 for example. Plate cylinder 122 may print the cyan image for A2, A7, while plate cylinder 124 prints the cyan image for A3, A4 and plate cylinder 126 the cyan image for A4, A5. Magenta, yellow and black can, for example, be printed by the other print couples.
To check the attributes of the newspaper, an operator would take one of the newspapers 10, and lay it on an analysis table. In a page mode, the operator would typically start with A1, check its attributes and make any changes to the ink keys or registration, then flip to pages A2:A3 and check both of the these pages, then check pages A4:A5, and then the pages A6:A7 and finally the rear page A8.
If the operator in the page mode, for example, alters the lateral register of the plate cylinder 120, the register of both pages A1 and A8 is affected. Thus an operator flipping through newspaper 10 in page mode might correct the lateral register for the cyan for page A1, which alters the lateral register for both page A1 and page A8, as they are printed by the same plate cylinder. When the operator flips to page A8 and notices that the register is improper, the operator may make the mistake of again correcting the register for page A8, even though this has already been corrected. Both image A1 and A8 thus may end up out of register, as shown schematically in FIG. 3, which shows multi-plate plate cylinder 120 moving laterally with both images A1 and A8.
While a two-tower printing press is described above, the same problem results in a four-image-wide printing press where some of the images are registered together, i.e. where each image on a plate cylinder is not independently registerable.
An object of the present invention is to permit an operator to accurately adjust the register in a multi-plate printing press where at least two images arc registered together.
Another alternate or additional object of the present invention is to reduce mistaken duplication of registration commands during a page mode.
The present invention provides a method for controlling a printing press having a first image cylinder for providing at least a first cylinder first image and a first cylinder second image to a printed material and a second image cylinder for providing at least a second cylinder first image and a second cylinder second image to the printed material, the method comprising the steps of:
printing a book having individual pages with the first cylinder first image, first cylinder second image, second cylinder first image and the second cylinder second image,
providing a first operational mode to an operator of the printing press, the first operational mode permitting the operator to review the pages with the first cylinder first image and the first cylinder second image of the book at the same time and to alter the registration of the first image cylinder providing the first cylinder first image and first cylinder second image, the first operational mode also permitting an operator to review the pages with the second cylinder first image and the second cylinder second image at the same time and to alter the registration of the second image cylinder providing the second cylinder first image and second cylinder second image; and
providing a different second operational mode to the operator for altering characteristics of the individual pages of the book.
By providing a first operation mode, referred to herein as the book mode, the user can flip through folios of a section to set the register for the folio. For example, with the eight-page book of FIG. 1, the user can place the folio with A1:A8 on the analysis table, alter the registration for the cylinder 120 printing A1:A8, then move the folio with A1:A8 to the side and place the folio with A3:A6 on the analysis table and alter the registration of cylinder 124. The operator then can flip the A3:A6 folio to alter the registration for A4:A5 via cylinder 126 and then retrieve the A1:A8 folio and flip to review A2:A7 for proper registration of cylinder 128. Alternately, the operator could have flipped the A1:A8 folio and checked A2:A7 and then discarded the folio before proceeding to the A3:A6 folio. The operator can retrieve further check copies from the printing press to ensure proper registration.
Once registration in the book mode is proper, the operator can move to the second operation mode, referred to herein as page mode, and use another check copy of the book to flip through the pages A1 to A8 in normal fashion to adjust ink zones and fountains, dampening zones and any other features to correct the page image.
The present invention advantageously permits the operator to correct registration of multi-plate plate cylinders by viewing the actually images at one time printed by the plate cylinder, and thus can reduce confusion caused by having the operator register the pages in a page mode.
The book mode preferably occurs before the page mode.
Preferably, the folio placed on the analysis table during book mode is automatically identified and correlated to a specific image cylinder.
Preferably, the printing press has additional multi-image image cylinders, the book mode permitting registration correction for folios printed by the additional image cylinders, and the page mode permitting individual page correction.
The present invention also provides a printing press comprising a first image cylinder for providing at least a first cylinder first image and a first cylinder second image to a printed material and a second image cylinder for providing at least a second cylinder first image and a second cylinder second image to the printed material, and a control unit for controlling the printing press. The control unit includes a first operational mode, the first operational mode permitting review of pages with the first cylinder first image and the first cylinder second image of the book at the same time. The control unit can control a registration unit for altering the registration of the first image cylinder having the first cylinder first image and first cylinder second image, as a function of an operator input while in the first operational mode. The first operational mode also permits an operator to review the pages with the second cylinder first image and the second cylinder second image at the same time and to alter the registration of the second image cylinder having the second cylinder first image and second cylinder second image. The control unit also provides a different second operational mode to the operator for altering characteristics of the individual pages of the book.
Preferably, the control unit includes an analysis table for receiving pages of a printed book, and a scanning unit for scanning pages of the book. In book mode, the control unit can identify the scanned pages and correlate them with one of the image cylinders. For example, the control unit can store the images on each of the image cylinders, and compare the scanned images from the analysis table during book mode to the stored images. The control unit can then identify the proper registration unit to send registration commands to.
The control unit can receive inputs from a user interface displaying the current operational mode, the user interface permitting the operator to select the book or page operational mode.
The printing press may include a lateral registration device for each image cylinder, the lateral registration device registering at least two images together. Preferably, the images on the multi-image image cylinder are not individually registerable.
Preferably, the printing press is an offset lithographic web printing press and the image cylinders are plate cylinders.
Image cylinder as defined herein includes any type of cylinder for providing an image, such as a plate cylinder.